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| Category: Eddy Current | Page: 1 of 1 | |
 Eddy Current |
Files: 9 | |
Files:
 Analysis of Eddy Current Signals 
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| Changes in an electrically conductive material close to a coil containing an alternating current can affect the resultant electromagnetic field from that coil. These material changes can be detected by monitoring the alternating current in the coil or using a separate sensing coil to monitor the resultant electromagnetic field. Changes so detected are the eddy current inspection signals. These signals can be analyzed for information relevant to the inspection being conducted. |
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2010-07-17 575.24 KB 47 |
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| Conductivity Measurement by Eddy Current
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| For determination of electrical conductivity under production and field conditions, eddy current instrumentation is employed. The eddy current instruments are calibrated against standards of known conductivity. When available, instruments designed specifically for measurement of conductivity are used. |
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2010-07-17 66.33 KB 30 |
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| Eddy Current Advances
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| Advaces in electromagnetic test methods. |
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2010-07-17 35.29 KB 26 |
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| Eddy Current Systems
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| Eddy current systems generally consist of three subsystems. One is the probe or probe subsystem. Second is the eddy
current instrument. The third is the accessory subsystem. Scanners and recorders are included in items considered
accessories. |
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2010-07-17 272.7 KB 35 |
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| Factors Effecting Eddy Currents
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| Eddy currents are generated when a varying magnetic field penetrates an electrically conductive material. The usual
source of the varying magnetic field is the electromagnetic field produced by a coil carrying an alternating electric
current. This field is called electromagnetic because it has both electric and magnetic field components; however only the magnetic component is involved in the generation of eddy currents. The rate at which the electromagnetic field
varies is called the frequency. The strength of the electromagnetic field at the surface of the conductor depends on the coil size and configuration, the amount of current through the coil, and the distance from the coil to the surface. |
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2010-07-17 311.05 KB 98 |
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| General Application of Eddy Current
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| Eddy current techniques are particularly well suited for detection of service-induced cracks in aircraft related materials in the field. Eddy current equipment is very portable, with many systems utilizing battery power. Eddy current inspection has greatest application for inspecting small localized areas where possible crack initiation is suspected rather than for scanning broad area of metal for randomly oriented cracks. In some instances, however it is more economical to scan relatively large areas with eddy current rather than to strip surface coatings, inspect by another method, and then refinish. |
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2010-07-17 541.9 KB 94 |
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| Introduction to Eddy Current Testing
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| Eddy current is used detect discontinuities in parts that are conductors of electricity. An eddy current is the circulating electrical current induced in a conductor by an alternating magnetic field. When eddy currents encounter an obstacle, such as a crack, the surrounding currents become distorted. This change is detected on a meter or other type of display. |
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2010-07-17 73.65 KB 50 |
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| Specific Application of Eddy Current Test
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| Specific Application of Eddy Current Test. |
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2010-07-17 51.24 KB 38 |
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| Thickness Measurement of Eddy Current
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| In general, three types of thickness measurement may be performed by eddy current techniques. The total thickness of thin metallic products such as foils, strip and sheet, may be determined when the thickness dimension is less than the
effective depth of penetration of eddy currents in the material. A second category of thickness measurement includes the measurement of metallic plating or coating on a conductive or magnetic base. Subcategories of plating and coating measurements can be established on the basis of the relative conductivity or permeability of the plating and the base metal on which it is plated. |
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2010-07-17 47.38 KB 21 |
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